Abstract: Apparatus for removing sludge from an underwater deposit comprises a blade having a cutting edge that points forwards and a blade surface to the rear of the cutting edge that faces the interior of a housing. Nozzles are positioned and oriented to direct jets of water onto the blade surface to fluidize sludge that has been cut by the blade. The jets have a component of motion in the rearward direction relative to the blade surface, whereby the fluidized sludge is effectively contained within the housing and high collection rates can be achieved. The apparatus can be adapted for horizontal use over the surface of a sludge deposit or for movement in any direction through a bulk sludge deposit.